1. Field of the Invention
This invention relates to semiconductor memory devices and more particularly to improved design of EEPROM and flash EPROM devices.
2. Description of Related Art
In the present state of the art, the current charge erasing amount can not be well controlled by time due to the complex equation of F-N (Fowler-Nordheim) tunneling on the electric field across the tunneling oxide.
An object of this invention is providing precise multistate (1 cell, 2 bits) for E2PROM and Flash EPROM devices.
An object of this invention is to improve charge control by a P-N junction which is fabricated by implant floating gate of EEPROM (E2PROM) and Flash EPROM.